Rf system concept for vehicular radar having several beams

ABSTRACT

ABSTRACTA transceiver ( 20 ) for a millimeter wave signal, consisting of a PCB ( 140 ) having PCB microstrip lines ( 141 ) and PCB waveguide apertures ( 159 ), and one or more transmitter modules ( 22 ) and one or more receiver modules ( 24, 26, 28 ) mounted on the PCB. Each module has a single microstrip-waveguide transition ( 34, 48 ) and a microstrip-microstrip transition ( 47, 49 ). The microstrip-waveguide transition of each module couples to one of the PCB waveguide apertures via a PCB-module waveguide-waveguide transition ( 167 ). The microstrip-microstrip transition of each module couples to one of the PCB microstrip lines via a PCB-module microstrip-microstrip transition ( 165 ). The PCB-module transitions are low tolerance, facilitating implementation of the transceiver.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the benefit of U.S. Provisional PatentApplication No. 60/374,227, filed Apr. 19, 2002, which is incorporatedherein by reference.

FIELD OF THE INVENTION

The present invention relates generally to transceiver design, andspecifically to design of transceivers for millimeter wavelength wavesfor vehicular radars.

BACKGROUND OF THE INVENTION

Radar transceivers operating at millimeter wavelengths have been in usefor some time on vehicles, where they are installed to provide suchfeatures as warnings of obstacles that may not be visible to a driver ofthe vehicle, or for autonomous cruise control (ACC). Because of theiruse in vehicles, the transceivers have to comply with a number ofconstraints, which taken together make it extremely difficult toimplement a simple, efficient transceiver that is to be usable in a massmarket environment.

Some of the constraints are inherent to operating with millimeter waves,which are typically transmitted in waveguides, microstrips, or by shortwire bonds between components. The problems generated by the millimeter(mm) wavelengths include requirements for close tolerances for mm wavestructures such as the waveguides, microstrip chip adhesion, and wirebonds. Failure to meet these requirements leads to unwanted reflections,cross talk between adjacent components, and/or absorption in thetransceiver, with consequent degradation of received or transmittedsignals. Typical cross-talk in adjacent mm wave receivers can be of theorder of 15 dB or more.

Other constraints arise from the need to use the transceiver in avehicle. Vehicular use requires that the transceiver be mechanically andelectrically robust, be able to operate as an all-weather system, berelatively simple to construct, and preferably be relatively simple tomaintain. The latter constraints are necessary in order to keep the costof the transceiver to acceptable levels. The former constraints must bemet so that the transceiver continues to function in the vehicle.

In an article titled “A Compact Manufacturable 7677-GHz Radar Module forCommercial ACC Applications,” by Gresham et al., in IEEE Transactions onMicrowave Theory and Techniques, 49 (2001), the authors describe atransceiver module for a pulsed Doppler application. The module isswitched between transmitting and receiving modes. In the receivingmode, the module operates, inter alia, a mixer which mixes received76-77 GHz signals with local oscillator 76-77 GHz signals.

Modem vehicular radars typically require implementation of amulti-channel architecture. This leads to a complex multi-function frontend. The complexity and stringent requirements on the transceiver leadto high cost solutions which limit the applicability of the technology.

There is thus a need for a low-cost, simple system for vehicular radar.

SUMMARY OF THE INVENTION

It is an object of some aspects of the present invention to provide amethod and apparatus for transmitting and receiving signals atmillimeter wavelengths.

In preferred embodiments of the present invention, a transceiver whichtransmits and receives millimeter (mm) waves comprises one or moretransmitter modules and one or more receiver modules. Each transmittermodule comprises active transmit components which are mounted on atransmit dielectric substrate and are configured so that the onlycoupling of the transmitter module that conveys mm wave signals is onemicrostrip-waveguide transition of the module. Each transmitter modulealso comprises a microstrip-microstrip transition for conveying lowfrequency signals. Each receiver module, which may operate in aheterodyne or a homodyne mode, comprises active receive components,including a mixer, which are mounted on a receive dielectric substrate,in a generally similar manner to the transmitter module. The activereceive components are configured so that the only coupling of thereceiver module that conveys mm wave signals is one microstrip-waveguidetransition of the module. Each receiver module also comprises amicrostrip-microstrip transition for conveying low frequency signals tothe mixer.

The transceiver also comprises a printed circuit board (PCB) which isconfigured to accept the transmitter and receiver modules. For eachmodule the PCB comprises a waveguide aperture which mates with arespective microstrip-waveguide transition to form a waveguide-waveguidetransition to a mm wave transmit port in the case of transmittermodules, and a mm wave receive port in the case of receiver modules. ThePCB also comprises microstrip lines which mate with respectivemicrostrip-microstrip transitions of the modules to formmicrostrip-microstrip transitions to low frequency inlet ports.

Minimizing the number of couplings within the modules that are used inconveying and transferring mm waves eases the component tolerancesrequired to produce transmitters and receivers with reproduciblecharacteristics. Using similar construction methods for the transmitterand receiver modules facilitates the treatment needed for thesecomponents, and similarities of the overall design of the modulessimplifies implementation of the transceiver. Furthermore, using onlymicrostrip-microstrip transitions and waveguide-waveguide transitionsfor coupling the modules to the PCB, both types of transitions needingrelatively low tolerances, considerably reduces assembly costs for thetransceiver.

In some preferred embodiments of the present invention, at least some ofthe receiver modules comprise multiple sub-receivers. Each sub-receivercomprises one microstrip-waveguide transition connected to a respectivemixer. The mixers receive a local oscillator (LO) low frequency inputvia the single microstrip-microstrip of the module. A single frequencygenerator provides a reference frequency for the LO low frequency, whichmixers of all the modules use.

The active components of the modules most preferably use microwaveintegrated circuit (MIC) technology to simplify mounting of thecomponents on their respective dielectric substrates. An optional mmwave short for each microstrip-waveguide transition preferably also usesMIC technology for its mounting. The transmitter and the receivermodules are most preferably implemented as surface mounted technology(SMT) components, so that their coupling to the PCB is facilitated.

There is therefore provided, according to a preferred embodiment of thepresent invention, a transceiver for a millimeter wave signal,including:

-   -   a printed circuit board (PCB), including PCB microstrip lines        and PCB waveguide apertures;    -   one or more transmitter modules mounted on the PCB, each        transmitter module including:    -   a single transmit microstrip-waveguide transition adapted to        convey millimeter waves and coupled to one of the PCB waveguide        apertures so as to form a transmit waveguide-waveguide        transition;    -   a transmit microstrip-microstrip transition coupled to one of        the PCB microstrip lines so as to form a PCB-transmitter module        microstrip-microstrip transition; and    -   transmit active components coupled to receive a first reference        frequency from the PCB-transmitter module microstrip-microstrip        transition, to generate the millimeter wave signal therefrom,        and to transmit the millimeter wave signal via the transmit        waveguide-waveguide transition; and    -   one or more receiver modules mounted on the PCB, each receiver        module including:    -   a single receive microstrip-waveguide transition adapted to        convey millimeter waves and coupled to one of the PCB waveguide        apertures so as to form a receive waveguide-waveguide        transition;    -   a receive microstrip-microstrip transition coupled to one of the        PCB microstrip lines so as to form a PCB-receiver module        microstrip-microstrip transition;    -   an output port; and    -   receive active components coupled to receive a second reference        frequency from the PCB-receiver module microstrip-microstrip        transition, to receive the millimeter wave signal from the        waveguide-waveguide transition, to generate a down-converted        signal in response to the second reference frequency and the        millimeter wave signal, and to transfer the down-converted        signal via the output port.

Preferably, the receive active components include:

-   -   a frequency multiplier that multiplies the second reference        frequency to produce a sub-harmonic of a millimeter wave        frequency; and    -   a mixer that receives the millimeter wave signal and the        sub-harmonic and generates the millimeter wave frequency        therefrom as a local oscillator frequency, and that generates        the down-converted signal in response to the local oscillator        frequency and the millimeter wave signal.

Preferably, at least one of the receiver modules includes a secondreceive microstrip-waveguide transition adapted to convey millimeterwaves and coupled to a second of the PCB waveguide apertures so as toform a second receive waveguide-waveguide transition.

Further preferably, the millimeter wave signal includes a firstmillimeter wave signal and a second millimeter wave signal, wherein thedown-converted signal includes a first down-converted signal and asecond down-converted signal, wherein the receive active componentsinclude:

-   -   a frequency multiplier that multiplies the second reference        frequency to produce a sub-harmonic of a millimeter wave        frequency;    -   a first mixer that receives the first millimeter wave signal and        the sub-harmonic and generates the millimeter wave frequency        therefrom as a local oscillator frequency, and that generates        the first down-converted signal in response to the local        oscillator frequency and the first millimeter wave signal; and    -   a second mixer that receives the second millimeter wave signal        and the sub-harmonic and generates the millimeter wave frequency        therefrom as a local oscillator frequency, and that generates        the second down-converted signal in response to the local        oscillator frequency and the second millimeter wave signal.

The transceiver preferably includes a coupling between the frequencymultiplier and the first and second mixers that rejects frequenciessubstantially similar to a frequency of the millimeter wave signal.

Preferably, at least one transmitter module is formed on a transmitdielectric substrate which retains the transmit active components, andat least one receiver module is formed on a receiver dielectricsubstrate which retains the receiver active components, and the transmitand receive dielectric substrates have substantially similar dimensions.

Preferably, at least one transmitter/receiver module includes:

-   -   a transmit/receive short adapted to act as a coherent reflector        for the transmit/receive microstrip-waveguide transition; and    -   a transmit/receive dielectric substrate which retains the        transmit/receive active components and the transmit/receive        short using microwave integrated circuit (MIC) technology.

At least one transmitter/receiver module preferably includes:

-   -   a transmit/receive dielectric substrate which retains the        transmit/receive active components;    -   a transmit/receive microstrip line; and    -   ground vias which penetrate the transmit/receive dielectric        substrate,    -   and wherein the transmit/receive microstrip-microstrip        transition consists of the ground vias and the transmit/receive        microstrip line.

At least one transmitter/receiver module preferably includes:

-   -   a transmit/receive dielectric substrate which retains the        transmit/receive active components;    -   a transmit/receive waveguide opening in the transmit/receive        dielectric substrate; and    -   waveguide vias which penetrate the transmit/receive dielectric        substrate, and wherein the transmit microstrip-waveguide        transition consists of the transmit/receive waveguide opening        and the waveguide vias.

At least one PCB waveguide aperture preferably includes:

-   -   a PCB waveguide opening in the PCB; and    -   waveguide vias which penetrate the PCB and surround the PCB        waveguide opening.

There is further provided, according to a preferred embodiment of thepresent invention, a method for transmitting and receiving a millimeterwave signal, including:

-   -   forming in a PCB PCB microstrip lines and PCB waveguide        apertures;    -   mounting one or more transmitter modules on the PCB, each        transmitter module including:    -   a single transmit microstrip-waveguide transition adapted to        convey millimeter waves and coupled to one of the PCB waveguide        apertures so as to form a transmit waveguide-waveguide        transition;    -   a transmit microstrip-microstrip transition coupled to one of        the PCB microstrip lines so as to form a PCB-transmitter module        microstrip-microstrip transition; and    -   transmit active components coupled to receive a first reference        frequency from the PCB-transmitter module microstrip-microstrip        transition, to generate the millimeter wave signal therefrom,        and to transmit the millimeter wave signal via the transmit        waveguide-waveguide transition; and    -   mounting one or more receiver modules on the PCB, each receiver        module including:    -   a single receive microstrip-waveguide transition adapted to        convey millimeter waves and coupled to one of the PCB waveguide        apertures so as to form a receive waveguide-waveguide        transition;    -   a receive microstrip-microstrip transition coupled to one of the        PCB microstrip lines so as to form a PCB-receiver module        microstrip-microstrip transition;    -   an output port; and    -   receive active components coupled to receive a second reference        frequency from the PCB-receiver module microstrip-microstrip        transition, to receive the millimeter wave signal from the        waveguide-waveguide transition, to generate a down-converted        signal in response to the second reference frequency and the        millimeter wave signal, and to transfer the down-converted        signal via the output port.

The present invention will be more fully understood from the followingdetailed description of the preferred embodiments thereof, takentogether with the drawings, a brief description of which follows.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic block diagram of a millimeter wave multiple beamtransceiver, according to a preferred embodiment of the presentinvention;

FIG. 2 is a schematic block diagram of an alternative millimeter wavemultiple beam transceiver, according to a preferred embodiment of thepresent invention;

FIG. 3 is a schematic exploded drawing of a transmitter module of thetransceiver of FIG. 1 or 2, according to a preferred embodiment of thepresent invention;

FIG. 4 is a schematic cross-section of the transmitter module of FIG. 3,according to a preferred embodiment of the present invention;

FIG. 5 is a schematic diagram of conducting layers of the transmittermodule of FIG. 3; and

FIG. 6 is a schematic diagram of a section of a printed circuit board ofthe transceiver of FIG. 1 or 2, according to a preferred embodiment ofthe present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Reference is now made to FIG. 1, which is a schematic block diagram of amillimeter wave multiple beam transceiver 20, according to a preferredembodiment of the present invention. Transceiver 20 comprises atransmitter module 22 which generates millimeter (mm) waves, atfrequencies of the order of W-band, the mm waves being coupled to atransmitting antenna via a mm wave microstrip-waveguide transition 34,which acts as a mm wave output port. Herein, millimeter (mm) waves areassumed to be waves having frequencies of the order of W-band. In orderto generate its mm waves, transmitter 22 receives a low frequency (LF)reference signal, at frequencies of the order of 12 GHz, from afrequency synthesizer 32. The LF signal is received via amicrostrip-microstrip transition 47, which acts as an LF inlet port totransmitter module 22.

Transmitter 22 comprises a x3 frequency multiplier 36, a first amplifier38, a x2 frequency multiplier 40, and a second amplifier 42, connectedin series. Components 36 and 38 are incorporated into a first integratedcircuit (IC) component 37. Components 40 and 42 are incorporated into asecond IC component 41. IC components 37 and 41 are in turn mounted on adielectric substrate 23, forming the base of a chip-scale package.Transmitter 22 is preferably implemented using microwave integratedcircuit (MIC) technology. It will be understood that the only mm waveconnection for transmitter 22 is for the output of the transmitter, viamicrostrip-waveguide transition 34 of the transmitter. A more detaileddescription of the physical layout and construction of transmittermodule 22 is given below, with respect to FIGS. 3, 4 and 4. It will beunderstood that while transceiver 20 comprises one transmitter module22, other transceivers having more than one transmitter module,generally similar to transmitter module 22, may be implemented. All suchtransceivers are assumed to be comprised within the scope of the presentinvention.

Transceiver 20 comprises a plurality of mm wave heterodyne receivermodules, each of which is constructed to receive one or more mm wavesignals, or channels, from respective input ports, typically antennas,of the transceiver. By way of example, transceiver 20 is assumed tocomprise three receiver modules 24, 26, and 28. Receiver 24 isconstructed to receive one mm wave signal. Receivers 26 and 28respectively comprise three sub-receivers and two sub-receivers of mmwave signals. It will be appreciated that the plurality of mm wavereceiver modules in transceiver 20 may comprise substantially any numberof receiver modules, and that each receiver module may have any suitablenumber of sub-receivers and corresponding input ports. Thus, forexample, alternative arrangements for receiving six mm wave inputsignals could be two receiver modules each having three sub-receiversand their input ports, three receiver modules each having twosub-receivers and their input ports, or six receiver modules each havingone input port.

Receiver module 24 comprises a x3 frequency multiplier 44 and anamplifier 46. Preferably, multiplier 44 and/or amplifier 46 aresubstantially similar in physical dimensions to multiplier 36 andamplifier 38, and are advantageously implemented as a single IC 45.Multiplier 44 receives a first LF signal (LO1) from synthesizer 32 via amicrostrip-microstrip transition 49, which acts as an LF inlet port toreceiver module 24, and which is implemented in substantially the samemanner as microstrip-microstrip transition 47. The value of frequencyLO1 is dependent on the output frequency transmitted by transmitter 22,as described in more detail below. An amplified output from amplifier46, having a fundamental frequency, is fed to a mixer 50, preferablyformed as an IC component, via a coupling line 56. Mixer 50 is alsocoupled to receive mm wave signals via a mm wave microstrip-waveguidetransition 48, which acts as a mm wave input port, and which isimplemented in substantially the same manner as microstrip-waveguidetransition 34. Mixer 50 mixes its mm wave input with a harmonic,preferably a second harmonic, of the fundamental frequency of amplifier46 so generating an intermediate frequency (IF) signal. Thus mixer 50acts both as a mixer and as a harmonic generator, generating an LO mmwave frequency used by the mixer internally within the mixer. Becausethe fundamental frequency is a sub-harmonic of the LO mm wave frequency,unwanted radiation out of input port 48 is virtually eliminated.

Apart from the differences described below, the operation of receivermodules 26 and 28 is generally similar to that of receiver 24, such thatelements indicated by the same reference numerals in receiver modules24, 26, and 28 are generally identical in construction and in operation.Receiver modules 26 and 28 comprise three and two sub-receiversrespectively, each sub-receiver having a respective mixer 50. As forreceiver 24, each mixer 50 receives a mm wave signal via a respective mmwave microstrip-waveguide transition 48, and mixes its mm wave inputwith a harmonic of the fundamental frequency of amplifier 46 to generatea respective IF signal. For each receiver module the LO1 signal is inputto the module via respective microstrip-microstrip transitions 49. Eachmixer 50 receives the fundamental frequency via coupling lines 54 and52, the coupling lines being constructed according to a number of mixers50 in each receiver. Thus, coupling line 54 splits the output ofamplifier 46 in receiver 26 to three mixers 50, and coupling line 52splits the output of amplifier 46 in receiver 28 to two mixers 50.

As for receiver 24, each mixer 50 of receivers 26 and 28 acts both as amixer and as a virtual harmonic generator for its respective channel,generating an LO mm wave frequency used by the mixer internally withinthe mixer. Furthermore, because mixers 50 operate with a fundamentalfrequency which is a sub-harmonic of the LO mm wave signals, the radiofrequency LO isolation is very high, yielding very high cross-talkisolation between channels of the order of at least 30 dB.

The down-converted IF frequency generated by each mixer 50 is fed to arespective IF receiver block 30. Each receiver block 30 comprises an IFamplifier 74, which amplifies the output from its respective mixer 50,and feeds the amplified IF to a further mixer 58. Each mixer 58 receivesa second LF signal (LO2) from synthesizer 32, LO2 acting as a localoscillator for the mixer, and generates substantially base-band signals.The base-band signals are transferred via filters 60 and 64, andamplifiers 62 and 66, to an analog-to-digital converter (A/D) 76, whichprovides a digital signal corresponding to the received signal at arespective mm wave input port In a preferred embodiment of the presentinvention, a frequency Tx input from synthesizer 32 to x3 multiplier 36is swept around a center frequency of 12.75 GHz, so that the output oftransmitter 22 is centered on 76.5 GHz. The value of LO1 is set so thatthe IF signal from mixer 50 is 2.4 GHz, so that LO1 is swept around(76.5−2.4)/6=12.35 GHz, and so that the fundamental frequency fromamplifier 46 is swept around 37.05 GHz. To generate the base-bandsignals in receiver block 30, LO2 is set to the value of the IF signalfrom mixer 50, i.e., 2.4 GHz.

Modules 22, 24, 26, and 28, as well as receiver blocks 30, synthesizer32, and A/D converters 76 are mounted on a printed circuit board (PCB)140. PCB 140 is configured to have a respective waveguide aperturecorresponding to each microstrip-waveguide transition 34 and 48. A moredetailed representation of one such waveguide aperture is describedbelow, with reference to FIG. 6. PCB 140 also comprises microstrip lines141 which are configured on the PCB so as to provide input signals totransmitter module 22 and receiver modules 24, 26, and 28. Microstriplines 141 feed the respective modules via microstrip-microstriptransitions 47 and 49.

It will be appreciated that transceiver 20 has only a single mm wavetransmitter connection, i.e., microstrip-waveguide transition 34, and asingle mm wave receiver connection per receiver or sub-receiver, i.e.,microstrip-waveguide transition 48.

It will also be appreciated that modules 22, 24, 26, and 28, are formedin a generally similar manner, each having a minimal number of closetolerance microstrip-waveguide transitions. However, themicrostrip-waveguide transitions of each module are coupled to waveguideapertures in PCB 140 by respective waveguide-waveguide transitions, andsuch waveguide-waveguide transitions may have substantially lowertolerances than microstrip-waveguide transitions without appreciabledegradation of signals transferred via the waveguide-waveguidetransitions. Thus, transceiver 20 may be implemented as a low-costsystem by coupling modules 22, 24, 26, and 28 to PCB 140. Mostpreferably, modules 22, 24, 26, and 28 are implemented as SMTcomponents, thus enabling the modules to be easily and accuratelymounted on PCB 140.

FIG. 2 is a schematic block diagram of a millimeter wave multiple beamtransceiver 80, according to a preferred embodiment of the presentinvention. Apart from the differences described below, the operation oftransceiver 80 is generally similar to that of transceiver 20 (FIG. 1),so that elements indicated by the same reference numerals in bothtransceivers 80 and 20 are generally identical in construction and inoperation. In contrast to transceiver 20, receivers 24, 26, and 28 intransceiver 80 operate as homodyne receivers. Thus, synthesizer 32 isimplemented to only produce a single frequency, which is effectivelymultiplied by a factor of six in transmitter 22, as described above. Inreceiver modules 24, 26, and 28 the single frequency is multiplied by afactor of three, and this x3 frequency acts as a fundamental frequencywhen it is coupled to mixers 50. As for transceiver 20, the mixersfunction both as mixers and as second harmonic producers of thefundamental frequency. In transceiver 80, the second harmonic frequencygenerated by each mixer 50 is substantially equal to the centerfrequency transmitted by transmitter 22.

Mixers 50 thus operate as homodyne mixers, generating substantiallydown-converted base-band frequencies. In contrast to IF receiver blocks30, receiver blocks 84 are therefore implemented to operate as base-bandreceivers, and consequently do not require a separate mixer (mixer 58)in order to generate base-band signals. Each receiver block 84 comprisesa base-band amplifier 82, most preferably a low noise amplifier, whichgenerates a base-band output similar to that generated by mixer 58 oftransceiver 20. The base-band signal is then processed by elements 60,62, 64, and 66, and A/D 76, substantially as described for transceiver20.

It will be appreciated that transceiver 80 requires fewer componentsthan transceiver 20, by virtue of operating in a homodyne mode. However1/f noise generated in mixers 50 in transceiver 80 may be relativelyhigh compared to 1/f noise generated in mixers 50 in transceiver 20,since the mixer output is effectively at base-band frequencies in thehomodyne transceiver, compared to IF values of approximately 2 GHz inthe heterodyne transceiver. To overcome this, the power output fromtransmitter module 22 in transceiver 80 may be increased compared tothat of transceiver 20, so as to overcome the increased 1/f noise. Othermethods for compensating for the 1/f noise are also known in the art.

FIG. 3 is a schematic exploded drawing of transmitter module 22, FIG. 4is a schematic cross-section of the module, and FIG. 5 illustratesstructure of surfaces within the module, according to a preferredembodiment of the present invention. Transmitter module 22 is formed bymounting components on a base 142. Base 142 comprises dielectricsubstrate 23, having an upper conducting layer 100 and a lowerconducting layer 101. The dielectric substrate and its upper conductinglayer act as a mounting plate for the components of transmitter module22. A similar base is advantageously also used as a foundation forreceiver modules 24, 26, and 28. Regions of layers 100, 101, are removedfrom the layers to accommodate mounting of elements on base 142, andalso to form elements within the base, as is described in more detailbelow.

Base 142 comprises microstrip-microstrip transition 47 andmicrostrip-waveguide transition 34. In layer 101 a first central hotmicrostrip section 146 is formed. Section 146 is connected to a secondcentral hot microstrip section 102, which is formed as a generallylinear “island” in layer 100. Section 102 is connected to section 146 bya transition “hot” via 106 penetrating dielectric 23. A ground path fortransition 47 is provided by vias 148, which form a pattern around hotvia 106, and which also penetrate dielectric 23. For clarity, only endsof vias, apart from via 106, are shown in FIGS. 3, 4, and 5. Vias 148connect conducting layer 101 to a grounding shield 115 formed inconducting layer 100, and are positioned so they do not contact islandsection 102.

Microstrip-waveguide transition 34 is formed by removing a generallyT-shaped section 150 of layer 100, while leaving a generally Y-shapedconducting section 118 in the center of insulating section 150. Section118 acts as a central radiator of transition 34. Around the “head” ofsection 150 are formed a plurality of vias 124 which couple layers 101and 100. Within layer 101 a generally rectangular opening 154 is formed,aligned with the head of T-shaped section 150.

Transition 34 most preferably further comprises a “back short” 121,comprising a conducting generally “U” shaped element 120 with a lid 122on the U-shaped element. The back short is dimensioned and positioned toact as a coherent reflector of mm waves, and prevents unwanted radiationleaking from transition 34 into the transmitter. Most preferably, backshort 121 is formed as an MIC component, which is coupled to a matingU-shaped region 164 formed on layer 100 of dielectric 23. Layer 100 alsocomprises generally rectangular shaped regions 160 and 162, the regionsbeing used for mounting of components 37 and 41 of transmitter module22. Layer 100 further comprises pads 166 and 168, insulated from shield115, which are used to couple DC levels to the components of thetransmitter module.

Transmitter module 22 also comprises a plurality of ground-ground vias114 coupling ground shield 115 to lower conducting layer 101.Ground-ground vias 114 penetrate substrate 23 and act both as heatdissipaters and mode suppressors.

Component 37 receives its LF input from an inert wire bond 110,preferably a gold wire, which is coupled to microstrip section 102.Section 102 is optionally coupled by a tab 108 to microstrip line 141 ofPCB 140, in which case section 146 of transition 47 may not be used. Theoutput of component 37 is transferred to component 41 by an inert wirebond 116. The mm wave output from component 41 is coupled by an inertwire bond 117 to central section 118 of transition 109. Power tocomponents 37 and 41 is provided by connecting inert bonds from pads 166and 168 to the components.

Transmitter module 22 most preferably has a covering 131 (only shown inFIG. 4, for clarity), comprising a housing wall 128 covered by a housinglid 130, mounted onto layer 100, the covering serving to protect thetransmitter. The covering also prevents radiation leaking from orentering the transmitter.

Receiver modules 24, 26, and 28 are implemented with substantiallysimilar techniques to those used for transmitter module 22. For allreceiver modules, individual components of the modules are mounted on abase substantially similar to base 142, and the components receive lowfrequency signals from their respective microstrip-microstriptransitions 49, and mm wave signals from their respectivemicrostrip-waveguide transitions 48. By way of example, implementationof receiver module 24 on base 142 is described hereinbelow.

Receiver module 24 comprises MIC components 45 and 50, which arerespectively mounted on regions 160 and 162 of base 142. Components 45and 50 are coupled substantially as described above for components oftransmitter module 22, so that receiver module 24 receives its LF inputfrom section 102, and components 45 and 50 are powered from pads 166 and168. In addition, the output of receiver module 24 is taken from mixer50 to a pad 170, and from pad 170 the mixer output is connected to theinput of IF receiver block 30 (FIG. 1).

Receiver modules comprising sub-receivers, such as receiver module 28and receiver module 26, are constructed in a substantially similarmanner to receiver module 24, except for differences stated below.Components of such receiver modules are most preferably mounted on baseswhich generally similar to base 142, but are modified to accommodate theextra elements comprised in the multiple sub-receivers. For example, inthe case of receiver module 28, two mixers may be integrated into oneIC, and the single IC positioned in region 162. The modified base forreceiver module 28 also comprises two microstrip-waveguide transitions8, each substantially similar to transition 34. The outputs of the twomixers are transferred via separate pads 170.

Receiver modules 24, 26, and 28 most preferably have a coveringsubstantially similar to covering 131 coupled to their upper layer, toserve as a protecting cover for the receiver.

FIG. 6 is a schematic perspective diagram of a section of PCB 140,illustrating coupling of the PCB to transmitter module 22, according toa preferred embodiment of the present invention. PCB 140 comprises anupper layer 103 and a lower layer 158. PCB 140 comprises a rectangularopening 156, which is optionally plated through. Alternatively oradditionally, opening 156 is surrounded by waveguide forming vias 161,penetrating the PCB. Thus, opening 156 together with vias 161 forms awaveguide aperture 159 in the PCB. For clarity, only the ends of vias inPCB 140 are shown in FIG. 6.

PCB 140 also comprises a microstrip line 144 formed in layer 103, line144 corresponding to the part of microstrip line 141 (FIG. 1) coupled totransmitter module 22. Microstrip line 144 is surrounded by groundingvias 143. Vias 147 in PCB 140 act as heat transfer and mode suppressingvias.

In assembling transceiver 20 or transceiver 80, transmitter module 22 isaligned and connected with a landing area 149, so that waveguideaperture 159 aligns with microstrip-waveguide transition 34, so forminga waveguide-waveguide transition 167. Similarly, microstrip line 144aligns with microstrip 146 of microstrip-microstrip transition 47,forming a microstrip-microstrip transition 165 which couples line 141 ofPCB 140 and microstrip section 102 of transmitter module 22.Alternatively, if tab 108 is implemented, it connects section 102 tomicrostrip line 144. Thus, since waveguide-waveguide transition 163 andmicrostrip-microstrip transition 165, or the use of tab 108, requirerelatively low tolerances, transmitter module 22 may be simply coupledto PCB 140.

A waveguide 163 is coupled to a section of layer 158 surrounding opening156, the waveguide leading to a transmit antenna (not shown in FIG. 6).

Receiver modules 24, 26, and 28, are coupled to PCB 140 in substantiallythe same manner as described for transmitter module 22. For eachreceiver module, a landing area is outlined in PCB 140, and the moduleis aligned and connected with the landing area. Each receiver modulecoupling to PCB 140 thus forms a single microstrip-microstrip transitionsimilar to microstrip-microstrip transition 165. Each receiver orsub-receiver within a receiver module also forms a singlewaveguide-waveguide transition similar to waveguide-waveguide transition167 for each receiving unit. As for the transmitter module, alltransitions for the receiver modules require relatively low tolerances,so that transceiver 20 or 80 may be easily and simply implemented.

It will be appreciated that the preferred embodiments described aboveare cited by way of example, and that the present invention is notlimited to what has been particularly shown and described hereinabove.Rather, the scope of the present invention includes both combinationsand subcombinations of the various features described hereinabove, aswell as variations and modifications thereof which would occur topersons skilled in the art upon reading the foregoing description andwhich are not disclosed in the prior art.

1. A transceiver for a millimeter wave signal, comprising: a printedcircuit board (PCB), comprising PCB microstrip lines and PCB waveguideapertures; one or more transmitter modules mounted on the PCB, eachtransmitter module comprising: a single transmit microstrip-waveguidetransition adapted to convey millimeter waves and coupled to one of thePCB waveguide apertures so as to form a transmit waveguide-waveguidetransition; a transmit microstrip-microstrip transition coupled to oneof the PCB microstrip lines so as to form a PCB-transmitter modulemicrostrip-microstrip transition; and transmit active components coupledto receive a first reference frequency from the PCB-transmitter modulemicrostrip-microstrip transition, to generate the millimeter wave signaltherefrom, and to transmit the millimeter wave signal via the transmitwaveguide-waveguide transition; and one or more receiver modules mountedon the PCB, each receiver module comprising: a single receivemicrostrip-waveguide transition adapted to convey millimeter waves andcoupled to one of the PCB waveguide apertures so as to form a receivewaveguide-waveguide transition; a receive microstrip-microstriptransition coupled to one of the PCB microstrip lines so as to form aPCB-receiver module microstrip-microstrip transition; an output port;and receive active components coupled to receive a second referencefrequency from the PCB-receiver module microstrip-microstrip transition,to receive the millimeter wave signal from the waveguide-waveguidetransition, to generate a down-converted signal in response to thesecond reference frequency and the millimeter wave signal, and totransfer the down-converted signal via the output port.
 2. A transceiveraccording to claim 1, wherein the receive active components comprise: afrequency multiplier that multiplies the second reference frequency toproduce a sub-harmonic of a millimeter wave frequency; and a mixer thatreceives the millimeter wave signal and the sub-harmonic and generatesthe millimeter wave frequency therefrom as a local oscillator frequency,and that generates the down-converted signal in response to the localoscillator frequency and the millimeter wave signal.
 3. A transceiveraccording to claim 1, wherein at least one of the receiver modulescomprises a second receive microstrip-waveguide transition adapted toconvey millimeter waves and coupled to a second of the PCB waveguideapertures so as to form a second receive waveguide-waveguide transition.4. A transceiver according to claim 3, wherein the millimeter wavesignal comprises a first millimeter wave signal and a second millimeterwave signal, and wherein the down-converted signal comprises a firstdown-converted signal and a second down-converted signal, wherein thereceive active components comprise: a frequency multiplier thatmultiplies the second reference frequency to produce a sub-harmonic of amillimeter wave frequency; a first mixer that receives the firstmillimeter wave signal and the sub-harmonic and generates the millimeterwave frequency therefrom as a local oscillator frequency, and thatgenerates the first down-converted signal in response to the localoscillator frequency and the first millimeter wave signal; and a secondmixer that receives the second millimeter wave signal and thesub-harmonic and generates the millimeter wave frequency therefrom as alocal oscillator frequency, and that generates the second down-convertedsignal in response to the local oscillator frequency and the secondmillimeter wave signal.
 5. A transceiver according to claim 4, andcomprising a coupling between the frequency multiplier and the first andsecond mixers that rejects frequencies substantially similar to afrequency of the millimeter wave signal.
 6. A transceiver according toclaim 1, wherein at least one transmitter module comprises a transmitdielectric substrate which retains the transmit active components, andwherein at least one receiver module comprises a receiver dielectricsubstrate which retains the receiver active components, and wherein thetransmit and receive dielectric substrates comprise substantiallysimilar dimensions.
 7. A transceiver according to claim 1, wherein atleast one transmitter module comprises: a transmit short adapted to actas a coherent reflector for the transmit microstrip-waveguidetransition; and a transmit dielectric substrate which retains thetransmit active components and the transmit short using microwaveintegrated circuit (MIC) technology.
 8. A transceiver according to claim1, wherein at least one receiver module comprises: a receive shortadapted to act as a coherent reflector for the receivemicrostrip-waveguide transition; and a receive dielectric substratewhich retains the receive active components and the receive short usingMIC technology.
 9. A transceiver according to claim 1, wherein at leastone transmitter module comprises: a transmit dielectric substrate whichretains the transmit active components; a transmit microstrip line; andground vias which penetrate the transmit dielectric substrate, andwherein the transmit microstrip-microstrip transition comprises theground vias and the transmit microstrip line.
 10. A transceiveraccording to claim 1, wherein at least one receiver module comprises: areceive dielectric substrate which retains the receive activecomponents; a receive microstrip line; and ground vias which penetratethe receive dielectric substrate, and wherein the receivemicrostrip-microstrip transition comprises the ground vias and thereceive microstrip line.
 11. A transceiver according to claim 1, whereinat least one transmitter module comprises: a transmit dielectricsubstrate which retains the transmit active components; a transmitwaveguide opening in the transmit dielectric substrate; and waveguidevias which penetrate the transmit dielectric substrate, and wherein thetransmit microstrip-waveguide transition comprises the transmitwaveguide opening and the waveguide vias.
 12. A transceiver according toclaim 1, wherein at least one receiver module comprises: a receivedielectric substrate which retains the transmit active components; areceive waveguide opening in the receive dielectric substrate; andwaveguide vias which penetrate the receive dielectric substrate, andwherein the receive microstrip-waveguide transition comprises thereceive waveguide opening and the waveguide vias.
 13. A transceiveraccording to claim 1, wherein at least one PCB waveguide aperturecomprises: a PCB waveguide opening in the PCB; and waveguide vias whichpenetrate the PCB and surround the PCB waveguide opening.
 14. Atransceiver according to claim 1, wherein at least one PCB microstripline comprises: a center microstrip line in the PCB; and ground viaswhich penetrate the PCB and surround the PCB center microstrip line. 15.A method for transmitting and receiving a millimeter wave signal,comprising: forming in a printed circuit board (PCB) PCB microstriplines and PCB waveguide apertures; mounting one or more transmittermodules on the PCB, each transmitter module comprising: a singletransmit microstrip-waveguide transition adapted to convey millimeterwaves and coupled to one of the PCB waveguide apertures so as to form atransmit waveguide-waveguide transition; a transmitmicrostrip-microstrip transition coupled to one of the PCB microstriplines so as to form a PCB-transmitter module microstrip-microstriptransition; and transmit active components coupled to receive a firstreference frequency from the PCB-transmitter modulemicrostrip-microstrip transition, to generate the millimeter wave signaltherefrom, and to transmit the millimeter wave signal via the transmitwaveguide-waveguide transition; and mounting one or more receivermodules on the PCB, each receiver module comprising: a single receivemicrostrip-waveguide transition adapted to convey millimeter waves andcoupled to one of the PCB waveguide apertures so as to form a receivewaveguide-waveguide transition; a receive microstrip-microstriptransition coupled to one of the PCB microstrip lines so as to form aPCB-receiver module microstrip-microstrip transition; an output port;and receive active components coupled to receive a second referencefrequency from the PCB-receiver module microstrip-microstrip transition,to receive the millimeter wave signal from the waveguide-waveguidetransition, to generate a down-converted signal in response to thesecond reference frequency and the millimeter wave signal, and totransfer the down-converted signal via the output port.
 16. A methodaccording to claim 15, wherein the receive active components comprise: afrequency multiplier that multiplies the second reference frequency toproduce a sub-harmonic of a millimeter wave frequency; and a mixer thatreceives the millimeter wave signal and the sub-harmonic and generatesthe millimeter wave frequency therefrom as a local oscillator frequency,and that generates the down-converted signal in response to the localoscillator frequency and the millimeter wave signal.
 17. A methodaccording to claim 15, wherein at least one of the receiver modulescomprises a second receive microstrip-waveguide transition adapted toconvey millimeter waves and coupled to a second of the PCB waveguideapertures so as to form a second receive waveguide-waveguide transition.18. A method according to claim 17, wherein the millimeter wave signalcomprises a first millimeter wave signal and a second millimeter wavesignal, and wherein the down-converted signal comprises a firstdown-converted signal and a second down-converted signal, wherein thereceive active components comprise: a frequency multiplier thatmultiplies the second reference frequency to produce a sub-harmonic of amillimeter wave frequency; a first mixer that receives the firstmillimeter wave signal and the sub-harmonic and generates the millimeterwave frequency therefrom as a local oscillator frequency, and thatgenerates the first down-converted signal in response to the localoscillator frequency and the first millimeter wave signal; and a secondmixer that receives the second millimeter wave signal and thesub-harmonic and generates the millimeter wave frequency therefrom as alocal oscillator frequency, and that generates the second down-convertedsignal in response to the local oscillator frequency and the secondmillimeter wave signal.
 19. A method according to claim 18, andcomprising a coupling between the frequency multiplier and the first andsecond mixers that rejects frequencies substantially similar to afrequency of the millimeter wave signal.
 20. A method according to claim15, wherein at least one transmitter module comprises a transmitdielectric substrate which retains the transmit active components, andwherein at least one receiver module comprises a receiver dielectricsubstrate which retains the receiver active components, and wherein thetransmit and receive dielectric substrates comprise substantiallysimilar dimensions.
 21. A method according to claim 15, wherein at leastone transmitter module comprises: a transmit short adapted to act as acoherent reflector for the transmit microstrip-waveguide transition; anda transmit dielectric substrate which retains the transmit activecomponents and the transmit short using microwave integrated circuit(MIC) technology.
 22. A method according to claim 15, wherein at leastone receiver module comprises: a receive short adapted to act as acoherent reflector for the receive microstrip-waveguide transition; anda receive dielectric substrate which retains the receive activecomponents and the receive short using MIC technology.
 23. A methodaccording to claim 15, wherein at least one transmitter modulecomprises: a transmit dielectric substrate which retains the transmitactive components; a transmit microstrip line; and ground vias whichpenetrate the transmit dielectric substrate, and wherein the transmitmicrostrip-microstrip transition comprises the ground vias and thetransmit microstrip line.
 24. A method according to claim 15, wherein atleast one receiver module comprises: a receive dielectric substratewhich retains the receive active components; a receive microstrip line;and ground vias which penetrate the receive dielectric substrate, andwherein the receive microstrip-microstrip transition comprises theground vias and the receive microstrip line.
 25. A method according toclaim 15, wherein at least one transmitter module comprises: a transmitdielectric substrate which retains the transmit active components; atransmit waveguide opening in the transmit dielectric substrate; andwaveguide vias which penetrate the transmit dielectric substrate, andwherein the transmit microstrip-waveguide transition comprises thetransmit waveguide opening and the waveguide vias.
 26. A methodaccording to claim 15, wherein at least one receiver module comprises: areceive dielectric substrate which retains the transmit activecomponents; a receive waveguide opening in the receive dielectricsubstrate; and waveguide vias which penetrate the receive dielectricsubstrate, and wherein the receive microstrip-waveguide transitioncomprises the receive waveguide opening and the waveguide vias.
 27. Amethod according to claim 15, wherein at least one PCB waveguideaperture comprises: a PCB waveguide opening in the PCB; and waveguidevias which penetrate the PCB and surround the PCB waveguide opening. 28.A method according to claim 15, wherein at least one PCB microstrip linecomprises: a center microstrip line in the PCB; and ground vias whichpenetrate the PCB and surround the PCB center microstrip line.